Method and apparatus for cleaning and storing endodontic tools

ABSTRACT

An endodontic instrument servicing system may comprise a socket-forming member that may include spaced wall members that define a socket. An at least partially open-cell foam body may be secured within the socket that is configured for cleaning contaminated instruments. The body may have an indentation force deflection greater than 120 pounds force (lbf) and be configured to substantially grip a rotating contaminated instrument in contact with the body without tearing the foam body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisonal of U.S. patent application Ser. No.13/601,855 filed Aug. 31, 2012 which claims priority to U.S. ProvisionalPatent Application Ser. No. 61/529,653 filed Aug. 31, 2011 and61/695,227 filed Aug. 30, 2012. The complete disclosures of eachapplication are hereby incorporated by reference in their entireties forall purposes. This application also incorporates by reference in itsentirety U.S. Pat. No. 8,231,734.

INTRODUCTION

Various industries use different types of instruments. In someindustries, the instruments may need to be maintained in a substantiallyclean state during use. However, use of the instruments may expose theinstruments to different types of contaminants, includingbio-contaminants, dust, dirt, grime, etc. It may be desired to quicklyand effectively reduce the level of contaminants on the instrumentsprior to, during or after use. For example, in the medical and/or dentalfields, instruments may need to be cleaned prior, during, and aftermedical and/or dental procedures.

As an example, dental instruments may require periodic servicing duringa dental maintenance and/or treatment procedure, such as an endodonticprocedure. During an endodontic cleaning procedure of a root canal, theendodontic instruments may collect various contaminants, such as dentinshavings, pulp tissue, canal debris, bacteria, bio-films, and/or variousmedicaments. It is important for dentists to continually clean theirinstruments of such materials to avoid reintroducing debris back into acanal. It is also important to keep the instruments clean to improve theshaping or cleaning capacity of the instrument.

In an endodontic procedure, dentists must also have continued, readyaccess to instruments, such as endodontic instruments (also referred toas files). The endodontic instruments may be used to gauge the depth ofroot canals prepared in a patient's teeth. Typically, a dental assistantis employed to hold an instrument dispenser from which the dentist canwithdraw sterile endodontic instruments.

Until about 2000, dentists could routinely perform endodontic cleaningand shaping of root canals by using stainless steel hand (also referredto as stationery) instruments. A hand instrument is very similar inappearance to a miniature drill bit, but the non-working end has a verysmall plastic handle to serve as a finger grip. These instrumentsgraduate in size from a tip diameter as small as about 0.06 mm upwardsto about 1.20 mm. They have very little taper to them and require manualhand and finger manipulation. These non-rotating (i.e., “stationery”)instruments were typically inserted into a root canal and with one'sfingers manually advanced into the canal using an action similar towinding a watch. This action serves to scrape the canal wall and therebyenlarge and shape it. Along with this shaping action, it is also servesto clean the canal walls by removing the pulp, microorganisms, debrisand other contaminants. These instruments are still used by dentiststoday, but in a much different and reduced role.

One way to clean contaminants from the endodontic instruments requiredwiping the instruments with a gauze sponge. Wiping the instrument withsuch a sponge may be inadequate to clean the instruments and may becumbersome.

Another way to clean contaminants from the endodontic instrumentsinvolved wiping the instruments on a foam cushion or inserting theinstruments into a foam cushion designed to capture the instrument andclean this material off. Typically the cleaning is accomplished byinserting an instrument into the foam cushion with an in and outstabbing action to clean the debris off the instruments. Removal of theinstrument after stabbing will leave the contaminant behind in the foamcushion. One such cushion for use in this method was disclosed in U.S.Pat. No. 8231734, which is hereby incorporated by reference. One suchcushion is identified commercially as the JORDCO® E-FOAM® foam. Thecushion of the '734 patent for this purpose was disclosed to have arecommended 25% indentation force deflection (IFD) within a range of80.00 to 120.00 pounds force (identified as N in the '734 patent butwhere units are pounds force) and a density in the range of 20 kg/m³ to30 kg/m³.

Around 2000, a new revolution in endodontic root canal therapy emerged.With the improvement in metallurgy, instruments started to appearconstructed of a nickel-titanium alloy. The alloy was selected forhaving incredible flexibility and memory, which allows the instrument tobe safely passed through a canal with great safety and efficiency. Earlyversions were supplied as hand instruments, but soon after they weremade to fit a motor driven rotary dental hand drill. It soon becameobvious that with proper training a dentist could experience superbresults with this new “rotary” root canal therapy technique. Examples ofrotary instruments for insertion into a dental hand drill include theGT.30-.06 and the Profile .775-.06, both by DENTSPLY® Tulsa Dental. Ofcourse, maintaining clean rotary instruments is equally as important asmaintaining clean stationery instruments.

SUMMARY

One or more embodiments of the present disclosure may include methodsand systems for cleaning and/or storing instruments. In an embodiment ofthe present disclosure, an endodontic instrument servicing system maycomprise a socket-forming member that may include spaced wall membersthat define a socket. An at least partially open-cell foam body may besecured within the socket that is configured for cleaning contaminatedinstruments. The body may have an indentation force deflection greaterthan 120 pounds force (lbf) and be configured to substantially grip arotating contaminated instrument in contact with the body withouttearing the foam body.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an embodiment of the present disclosure ofa dental instrument servicing system including a holder and a cushionconfigured to receive a rotary tip or flute portion of a drill.

FIG. 2 is an isometric view of an embodiment of the present disclosureof a holder configured to hold a cushion.

FIG. 3 is a section view of the holder of FIG. 2 showing internalprotrusions gripping an inserted cushion.

FIG. 4 is a front view of a cushion having characteristics found in theprior art, illustrating where a rotary tip of a dental drill has tornand grabbed a portion of the cushion after being rotated in contact withthe cushion.

FIG. 5 is a front view of a cushion of the present disclosure,illustrating where a rotary tip of a dental drill has not torn andgrabbed a portion of the cushion after being rotated in contact with thecushion.

FIG. 6 is a schematic illustration of the use of the cushion shown inFIG. 1 to clean a rotating instrument in an embodiment of a cleaningmethod of the present disclosure.

FIG. 7 is a schematic illustration of the use of the cushion shown inFIG. 1 to clean a rotating instrument in an embodiment of a cleaningmethod of the present disclosure.

DETAILED DESCRIPTION

As disclosed herein, a porous material is provided that enables storingand/or cleaning of instruments, including rotary and stationaryinstruments. The porous material may be used to clean instruments from avariety of industries, including, but not limited to, high-technologyindustries, medical industries, dental industries, etc. Recently, it hasbeen discovered that a superior way of cleaning some tools, such asendodontic tools, involves inserting the tool into a foam material,rotating the file tool, then withdrawing the tool from the foam and/orrotating the file when depressed horizontally onto the top of the foamand then withdrawing the file from the top of the foam. However, priorfoam products, such as the foam disclosed in U.S. Pat. No. 8,231,734,failed in this procedure because the foam breaks down and tears, leavingundesired and unacceptable dental debris and torn foam material on thefile when it is withdrawn from the foam. Recent studies havesurprisingly demonstrated that foam materials having higher density andforce deflection specifications yield improved cleaning functionalitywhen used in a procedure with a rotary file apparatus. This higherdensity foam can also still be used for storage of tools by having toolsinserted therein.

Although the following description illustrates the use of a porousmaterial in a dental instrument servicing system, it should beappreciated that a similar porous material may be used alone or in othertypes of servicing systems, such as medical, dental and high-technologyinstrument servicing systems. For illustration purposes, the porousmaterial may be mounted in such dental instrument servicing systemsdescribed and disclosed in U.S. Pat. Nos. 4,280,808, 5,368,482,6,036,490, and 8,230,994; and U.S. Patent Application No. 2011/0229843,all of the disclosures of which are hereby incorporated by reference.Each of those servicing systems includes a holder and cushion forinsertion into the holder. A cushion having the characteristics of thepresent disclosure may be used in replacement of the prior art cushiondescribed in those systems, as used in accordance with the methods andsystems of the present disclosure, as described in more detail below.

Referring to FIG. 1, an exemplary dental instrument servicing system 10is generally shown that may include a socket-forming member or holder 12configured to carry an insert or cushion 14, and a rotary dental drill15 having a rotary tip (or file or instrument or flute) 16 that isinsertable into cushion 14. The system may further include a fingermount 18 and a medicament holder 19 (see FIG. 2). Cushion 14, fingermount 18, and medicament holder 19 may be selectively removable from thesocket-forming member.

Socket-forming member 12 may be any device configured for holding acushion. Although not required, the socket-defining member may be ofunitary construction, being formed of a lightweight material such asplastic or aluminum. These materials, it will be appreciated, typicallyare inexpensive, may be formed by molding processes, and may be suitablefor hand-worn use.

In an embodiment shown in FIG. 2, socket-forming member 12 may includeplural walls that define a passage or socket 20. Socket-forming member12 may define a double-open-ended socket 20, which provides a seat forcushion 14. For example, front wall 22, side walls 24, 26, and back wall28 may form passage or socket 20. In some embodiments, cushion 14 may beremovably inserted into socket 20, retained by one or more of the wallsof socket forming member 12. Cushion 14 may be somewhat abrasive and/orhave a relatively rough surface such that the abrasiveness and/orsurface of the cushion may be frictionally retained within passage 20.The member may include one or more passages configured to carry one ormore cushions, as desired.

In some embodiments, the frictional engagement between cushion 14 andthe walls of passage 20 may be enhanced by the provision of one or moreprojections 30 disposed on the interior surface of one or more of thewalls of the socket 20 (see FIG. 3).

As shown in FIG. 2, finger mount 18 may be attached to socket-formingmember 12 and may allow the system to be positioned on an individual'sforefinger for use during a dental procedure. The finger mount may beremovably attached to socket-forming member 12 via a cooperative slidearrangement, as described in previously issued U.S. Pat. No. 4,280,808and US Application No. 2011/0229843, each of which have beenincorporated by reference above. Typically, such a system is relativelylightweight and is not appreciably more burdensome than a large ring.Thus, such a system typically will not significantly interfere with useof the wearer's hand.

Socket-forming member 12 also may include an outwardly projecting shelf32. Shelf 32 may extend outward covering finger mount 18 and may protecta user's finger from injury by sharp instruments, such as endodonticfiles, which may be inserted into cushion 14. The shelf may furtherserve as a measuring device for use in connection with endodontic files.Thus, shelf 32 may include a trough 34 for receipt of endodontic files.A scale 36 may be etched into shelf 34, accommodating accuratepositioning of depth markers on the file.

Medicament holder 19 may be removably applied to socket-forming member12. Medicament holder 19 may include a cup section configured to hold amedicament in a dosage container and a clip section (not shown)configured to selectively attach the medicament holder to thesocket-forming member.

The socket-forming member may include other features, such as a serviceplatform (not shown) adapted for receipt of depth markers.

FIGS. 1 and 3 illustrate an example of structural features of cushion14. Cushion 14 may be formed of a porous material, such as foam,suitable for use in holding and cleaning instruments, such as endodonticfiles. Cushion 14 may also include characteristics configured to notgrab, tear, or shred foam while instrument 16 is in contact with cushion14 while rotating.

Cushion 14 may include a surface configured to enable an instrument tobe inserted into the body of the cushion. Stationery and rotaryinstruments, such as rotary tip 16, may puncture the surface and bepushed into an interior region of the cushion (see middle panel of FIG.6, for example). The foam may be configured to enable instruments ofvarying shaft diameters and lengths to easily penetrate cushion 14. Thesurface of cushion 14 may be resilient, such that the surface is able torecover from the puncture and return to its prior state. The cushionsmay be described as “crisp” or “firm” such that the tip of an instrument(e.g., instrument 16) easily pierces the surface of cushion 14. Suchcushions may adequately resist collapsing when penetrated by aninstrument. Materials that collapse or resist the penetration of filesor other instruments may frustrate the user and are therefore consideredunsatisfactory.

Cushion 14 may be generally pie-shaped such that it conforms closely tothe shape of the socket. However, it should be appreciated that cushion14 may be any suitable shape depending on the system. Cushion 14 may beadapted to receive files of a predetermined size and/or style.Therefore, the system may be used to organize endodontic files, or otherinstruments, by placement of selected files into the cushion and/or toclean instruments, including rotary and stationery instruments, usingthe cushions, as will be described in more detail below.

A peripheral surface of cushion 14 may include a plurality of ridges orcorrugations 38 that may enhance the retention of cushion 14 withinpassage 20 of member 12. The corrugations may increase and/or enhancethe frictional engagement between the peripheral surface of the cushionand the interior surfaces of side walls 24, 26 and/or projections 30.Ridges or corrugations 38 may be rounded or they may include a pluralityof angularly intersecting flat surfaces that may provide a stepped orsaw tooth configuration, or any other configuration desired.

In some embodiments, cushion 14 may include one or more features toensure proper seating in socket 12. Proper seating may allow forproviding a specific desired density of cushion 14 and/or placement ofcushion 14 in socket 12. For example, the specific foam shape and/orcontour may ensure proper seating.

Cushion 14 may also include one or more ledges or seating shoulders 40that may align with a top surface of socket 14 or a seating shoulderindicator of socket 12. Ledges 40 may aid in proper positioning ofcushion 14 in socket 12.

Cushion 14 may also include a bulbous bottom or insertion tip 42configured to be pulled through an open bottom end of socket 12. Whenpulled through, bulbous bottom 42 may decompress and expand to a sizethat is larger than the open bottom end, thereby helping to securecushion 14 into socket 12 in a desired seated position. Precise andproper positioning of cushion 14 in holder 12 may keep the foam densityof cushion 14 precisely consistent so that files can be cleaned. Forexample, when tip 42 is pulled through the bottom of holder 12, cushion14 may lock into place in holder 12. This may allow for the foam to haveconsistently the same desired density each and every time it is seatedin holder 12.

Cushion 14 and socket 12 may include control features to ensure properseating of cushion 14 in socket 12. For example, cushion 14 may includetapered features that specifically seat into reciprocal tapered featuresin socket 12 to provide the desired seating. Cushion 14 may have atapered seating feature on the insertion end to assure precise mountingand density of the polyurethane open cell foam when in socket 12.Cushion 14 may have a tapered seating feature on the wider terminal endto assure precise mounting and density of the polyurethane open cellfoam when in socket 12.

As best seen in FIGS. 2 and 3, passage 20 may be shaped as a taperedlongitudinal channel. The tapered channel may provide a superior topworking surface for cushion 14, allowing for organizing, cleaning andtransferring endodontic instruments and to control the precisepositioning of cushion 14 in socket 12. The tapered channel may providepredictable compression of cushion 14 while generating retention forcesthat stabilize cushion 14 in socket 12.

Cushion 14 may have one or more raised features on each side that seatwithin reciprocal features of socket 12 to assure precise mounting anddensity of the polyurethane open cell foam when in socket 12. Thecontrol feature may include a plurality of bilateral solid taperedindentations.

In some embodiments, cushion 14 may be configured as part of a handheldor stand alone device. The socket-forming member, for example, may beconfigured as a handheld or stand-alone device. The cushion may be hardsurface mounted. The cushion may take any shape or form desired.

Cleaning of Rotating Instruments.

The characteristics of a porous material, such as cushion 14, areconfigured to allow for cleaning of a rotary instrument that is rotatingwhile in contact with the porous material. The reason for contacting arotating file with the porous material is to aid in the removal ofcontaminants from the file in an easy manner. A file cleaned by such amethod, however, should have the contaminants removed and also not haveany foam or other residue on the file after the cleaning. There areseveral ways a user may clean a rotating file using the porous material,including where a user may insert the rotating file into the cushionand/or where a user may depress the rotating file horizontally againstan outside surface of the cushion. The characteristics of the porousmaterial must be able to withstand these different types of cleaningmethods of rotating instruments while not tearing, grabbing, orshredding from the rotation of the instrument, which would leaveundesired foam, contaminants or other residue on the file, thusfrustrating the overall cleaning objective.

Failure of Prior Art Cushion Characteristics

While rotary instruments have become commonplace in endodontic practice,the prior art cushions have failed to allow for successful cleaning ofsuch instruments when the instrument is contacted with the foam whilerotating. It has been found that the characteristics of the prior artporous material, such as the cushion designed for cleaning thestationary instruments, could not withstand contact with a rotatinginstrument without tearing, grabbing, and/or shredding of the cushion,hence leaving undesired torn off foam on the tip after the removal ofthe tip from the prior art cushion.

For example, as illustrated in FIG. 4, it has been found that insertionof a rotating instrument into the prior art cushions disclosed in U.S.Pat. No. 8,231,734 (one such cushion is identified commercially as theJORDCO® E-FOAM® foam) tends to cause snagging as the file occasionallygrabs onto the cell structure of the low density cushion. This oftenresults in grabbing, tearing and/or shredding of the foam. For example,FIG. 4 shows a socket 100 holding a prior art cushion 102 and a rotatingtip 16 attached to a drill 15 (the rotation motion is shown by thecircular arrow) being removed upwards from prior art cushion 102. Tornoff portions 104 of the prior art cushion 102 remain on tip 16 uponremoval, which is undesired and unacceptable.

Likewise, a similar issue resulted from pressing a rotating filehorizontally against the top surface of a prior art cushion by applyinga slight amount of pressure during the cleaning procedure. The rotatingfile was slowly dragged or swiped on the foam horizontally during thisprocedure, causing the cushion to grab the file and in some cases totear and/or shred the foam. Torn off portions of the prior art cushionremain on the tip upon removal, which is undesired and unacceptable.

The above results of the prior art cushion were also confirmed bytesting the cleaning of two types of rotary files, a GT.30-.06(DENTSPLY® Tulsa Dental) and a Profile .775-.06 (DENTSPLY® TulsaDental). Both were tested in rotary tests where the files while rotatingwere placed in contact with the prior art JORDCO® E-FOAM® cushion. Thecushion had a 25% indentation force deflection (IFD) of around 104pounds force, along with a density, air flow and cell count, all withinthe range disclosed in U.S. Pat. No. 8,231,734 (N was meant as poundsforce in the '734 patent). During the testing, each file was mounted andtested using an electric motor hand piece set to a speed of 320 rpm. Atest piece of foam was mounted and fully seated into an ENDORING® IIcup. In one test, each rotating file was inserted or stabbed three timesinto the top faceted surface of the foam insert. The foam was observedfor any grabbing, tearing or shredding. In the second part of the test,each rotating file was drawn horizontally across the top faceted surfaceof the foam insert with a slight pressure applied to the file tosimulate a cleaning action. The results of the study were dramatic inthat the tests yielded a grabbing, tearing and/or shredding of the foambeing studied when a moving rotary file was inserted into or removedfrom the foam or drawn across the top surface of the foam in ahorizontal fashion. This left undesired torn off portions of the cushionon the file after the cleaning procedure was completed. Based on this,the prior art cushion could not be predictably used to clean rotatingfiles without the risk of grabbing, tearing and/or shredding of thecushion using these two techniques.

Hence, there exists a need for a cushion insert having characteristicsthat allow for cleaning of instruments in contact with the foam whilerotating or moving, but without snagging, tearing, grabbing, orshredding of the foam.

Characteristics of the Porous Material of the Present Disclosure

The characteristics of the foam of the present disclosure have yieldedsurprisingly beneficial results in solving the issues with the prior artcushions for cleaning instruments rotating in contact with the cushions.Tests have been conducted to determine the suitablecharacteristics/composition for cushion 14 to overcome the issues of theprior art. An exemplary foam which has been used successfully to cleanrotary files is described in TABLE 1 below:

TABLE 1 Characteristics of Porous Material/Cushion of the PresentDisclosure Density (pounds per cubic foot)  1.5-3.0 lbs/ft³ or(kilograms per cubic meter) 24.1-48.1 kg/m³ Material Cell Count   12-20cells/cm (cells per centimeter) Air Flow (cubic feet per minute) 0.1-5.0 ft³/min or (cubic decimeters per second)  0.05-2.4 dm³/sec 25%IFD  121-198 lbf Indentation Force Deflection (pounds force)

It should be appreciated that although an exemplary foam is described indetail, the composition of suitable cushions may vary. For example,suitable foams for use in the present disclosure may have a differentdensity, air flow, 25% indentation force deflection (IFD), compressionforce deflection (CFD), cubic feet per meter (CFM) rate, cell count,etc. Other characteristics, such as the compression force deflection(CFD), and/or tensile and/or tearing strength of a foam may also beconsidered. The foam characteristics, as described above, are includedonly for illustrative purposes and are not intended to include allsuitable compositions for cushion 14.

Generally, the foam characteristics may be balanced to achieve asuitable material for use in insertion and/or rotary cleaning ofinstruments. Selection of one or more of the density, material, and/orcell count of the foam may effect a change in the air flow, theindentation force deflection, the density, the compression forcedeflection, or other characteristics of the cushion. For example,selection of the appropriate material may include balancing the densityand cell count of the foam, such that the foam functions as desired.

The “firmness” of the cushions may be measured using the 25% indentationforce deflection (IFD) test according to the standard ASTM D 3574 TestB1: Specified Deflection. An IFD number represents the force required toindent a foam sample by a specified percentage (e.g. 25%) of itsoriginal thickness. As shown in TABLE 1 above, suitable foams have a 25%indentation force deflection of approximately 121 lbf to 198 lbf.

It further should be noted that the foam within the cushions may bedescribed in relation to their cubic feet per minute (CFM) values. CFMvalues may be obtained by determining the cubic feet per minute air flowthrough a standard 15×15×4″ thick test piece of foam used in the IFDtests. As shown in TABLE 1 above, suitable foams have a CFM value of 0.1ft³/min to 5.0 ft³/min (or 0.05 dm³/sec to 2.4 dm³/sec). Foams withother CFD values may be suitable as well.

In some embodiments, the cushion may be composed of polyurethane and/orurethane. The cushion may be composed of, and/or include, melamine. Thecushion may comprise and/or be made from other types of materials, suchas rubber, polyester, polyether, etc.

Polyurethane and/or urethane cushions may be able to withstand steamautoclaving without substantially deforming, melting, or producing anynoxious out-gassing of toxic substances during the steam autoclavingprocess. Moreover, polyurethane is widely and safely used in manymedical and dental applications.

As briefly noted above, in some embodiments, it may be desirable tosterilize the cushions (and the instruments) prior to use. For example,in many environments, steam autoclaving may be used to sterilize thecushions. Thus, the cushions may be configured to withstandsterilization via steam autoclaving prior to use. Due to the use of thecushions in medical and dental applications, the cushions typically maybe configured to withstand steam autoclaving as performed in clinicalenvironments, where the steam autoclaves typically operate within arange of between 275 degrees and 300 degrees F. and a range of between20 psi and 30 psi.

The cushions may include an at least partially open-cell foam body. Theat least partially open-cell body may allow steam from an autoclave topenetrate an interior region of the cushion. Penetration of the interiorregion enables steam to surround and effectively sterilize endodonticfiles or other instruments at least partially disposed within thecushion. Typically, substantially closed cell structures prevent steamfrom passing into the interior region of the cushion. Such closed cellcushions may not provide the necessary sterilization of the instrumentspositioned within the cushion. In contrast, cushions that have an airflow of more than approximately 1.0 dm³/second (as measured according tothe standard ASTM D 3574 Air Flow Test G) may be adequate to enablesterilization of endodontic files positioned in the interior region ofthe cushion. As shown in TABLE 1, the cushions have an air flow of about0.05 dm³/second to about 2.4 dm³/second.

Here, the cushion characteristics of the present disclosure have solvedthe grabbing, tearing and/or shredding problem found when contacting theprior art cushions with a rotating instrument for cleaning. For example,this is illustrated in FIG. 5, which shows that tip 16 of drill 15 lacksthe torn off portions 104 after being rotated in contact with cushion 14and withdrawn from cushion 14. Cushion 14 may include some, all, or acombination of one or more of the following characteristics: apolyurethane open cell foam with an IFD range of 121-198 lbf, and/or aweight density range of 24.1-48.1 kg/m³, and/or an air flow In the rangeof 0.05-2.4 dm³/second and/or any other characteristics disclosed inTABLE 1, used to clean and store endodontic instruments, which mayinclude rotary and/or hand endodontic instruments.

FIG. 6 schematically illustrates the instrument cleaning properties ofcushion 14. Generally, the abrasive action of the foam in a cushionfunctions to substantially clean instruments inserted therein. Morespecifically, the porous material in the cushion is configured to gripan instrument, such as a dental instrument attached to a rotary drill(indicated generally as instrument 16 and drill 15 in FIG. 6). Thegripping characteristics of the porous material substantially retainscontaminants and other residuals from the instrument.

For example, during a medical or dental procedure, an instrument mayaccumulate contaminants (also referred to as bioburdens) 44 that maycling to the file. For example, as shown in the left panel of FIG. 6,contaminants 44 may extend along the shaft of instrument 16. Insertionof instrument 16 into cushion 14 may occur by penetrating the surface ofcushion 14, as indicated by the downward arrow in the left panel. Drill15 may be rotating file 16 before penetrating the surface. Drill 15 mayinitiate rotation of file 16 after penetrating the surface.

The middle panel of FIG. 6 illustrates entry of instrument 16 into aninterior region of cushion 14. Contaminants 44 may be sloughed off ofshaft 16 as shaft 16 rotates in the cushion 14. The cells within thecushion are configured to substantially grip the file as it is insertedinto and pulled out of the cushion. In some embodiments, the drill maybe rotating at a speed of 100-1000 rotations per minute (RPM), thoughcharacteristics of cushion 14 may accommodate cleaning instrumentsrotating at an RPM outside this range.

In some embodiments, further cleaning of instrument 16 may include theremoval from and the reinsertion of shaft 16 to/into cushion 14, therebyrepeating the steps illustrated generally in FIG. 6. Multiple insertionsof the dental instrument into the cushion may function to substantiallydecrease the level of contaminants 42 on instrument 16. Hence,instrument 16 may be rotated in a first pass, then removed from cushion14. Instrument or file 16 may then be re-inserted into cushion 14 androtated again for another pass. One to five passes may be desirable fordifferent applications to ensure the file is clean, though the file maybe inserted for more passes as needed.

In some embodiments, instrument 16 is rotated in cushion 14 for about1-3 seconds per pass. It is also possible to rotate for longer than 3seconds, if needed. It is also possible to vary the time from pass topass as desired.

In some embodiments, the rotational direction of drill 15 may be variedas desired. For example, drill 15 may rotate instrument 16counterclockwise as shown in FIG. 6 before, during, and/or after theinsertion and removal of instrument 16 from cushion 14. Drill 15 mayrotate instrument 16 clockwise before, during, and/or after theinsertion and/or removal of instrument 16 from cushion 14. Drill 15 mayrotate instrument 16 with a mixture of counterclockwise and clockwiserotations as desired. Drill 15 may rotate instrument 16 counterclockwiseduring a first pass and then clockwise during a second pass, etc. asdesired.

By gripping the instrument as it is rotating in a cushion, thecontaminants may be displaced from the instrument to the cushion. Thecomposition of the cushion will affect the removal of contaminants fromthe instrument. Specifically, a foam having the characteristics found inTABLE 1 above may significantly reduce contaminants on an instrument.

As is shown in the right panel of FIG. 6, removal of instrument 16 fromcushion 14 results in contaminants 44 being left in cushion 14 as aresult of the cleaning method. Shaft 16 may be free or substantiallyfree of contaminants 44 and of torn off pieces of cushion 14 becausecushion 14 was configured with characteristics such that cushion 14would not tear, grab or shred upon contact with rotating instrument 16.

FIG. 7 illustrates an embodiment of a cleaning method where instrument16 may be contacted to cushion 14 by depressing instrument 16horizontally against the outer surface of cushion 14 rather thaninserting instrument 16 into the interior surface of cushion 14.Instrument 16 may be rotated before, during, and/or after contact ismade with cushion 14. As shown, instrument 16 is depressed betweenridges 38 of cushion 14, but instrument 16 could also be depressedacross ridges 38. The surface of cushion 14 could also be configuredwithout ridges or in any formation desired. Instrument 16 could bedepressed onto the surface in any way desired. Cushion 14 will grip andremove contaminents (such as contimanents 44) from cushion 14.Instrument 16 may be wiped on and/or swiped across the outer surface ofcushion 14, and/or held in one position, during rotation of instrument16 while depressed against cushion 14. Cushion 14 may have thecharacteristics described above that may allow cushion 14 not to tear,grab or shred upon contact with rotating instrument 16.

Instrument 16 may be rotated counterclockwise, clockwise, or a mixtureof both directions, as desired, before, during, and/or after contact ismade. Instrument 16 may be contacted with cushion 14 during rotation for1 to 5 seconds, or for any length of time desired. Instrument 16 may beremoved and re-depressed onto cushion 15 for 1 to 3 passes, or for asmany passes as desired. The direction of rotation can be varied asdesired during a pass and/or from pass to pass.

The method of inserting the instrument into the foam may be combinedwith the method of depressing the instrument horizontally against anoutersurface of the foam as desired. One or the other could go first andthen the method could be varied from pass to pass, such as byalternating if desired.

In some embodiments, a method may include providing a hand heldpolyurethane open cell foam with a 25% indentation force deflection(IFD) range of 121-198 lbf, and/or a weight density range of about24.1-48.1 kg/m³, and/or an air flow in the range of about 0.05-2.4dm³/sec used to clean and store endodontic instruments, which mayinclude rotary and/or hand endodontic instruments, that cleans therotating instrument by using a stabbing motion to pass the rotatinginstrument in and out of the polyurethane open cell foam one or multipletimes. The method may include insertion of the instrument into the foamand/or depressing the foam horizontally against an exterior surfacewhile instrument 16 is rotating to clean the instrument.

Testing confirmed that using the insertion and depression methods withthe cushions of the present disclosure did not result in grabbing,tearing, or shredding of the cushion by the rotating tips. Hence, thetips could be removed without foam portions remaining on the withdrawnfile.

Testing also confirmed that contaminants can be successfully removedfrom the file to clean the rotating file using either the insertion orthe depression method. Other testing also confirmed that a cleaningmethod involving inserting a rotating file into a cushion outperformedsimply inserting a stationery file to clean. Other testing similarlyconfirmed that a cleaning method involving depressing a rotating fileagainst the cushion outperformed depressing to wipe a stationery fileacross the cushion.

For example, the cushion of the present disclosure was found to cleanmore effectively than the prior art cushions using the traditionalnon-rotating stabbing method. A test was performed to gauge cleaningeffectiveness, with the results illustrated in TABLE 2 below.Specifically, the cleaning effectiveness was measured using biologicalserial dilution techniques. Accordingly, the level of bioburdens(contaminants) on the instrument was measured prior to, and afterinsertion and removal (also referred to herein as a stab) of theinstrument into and out of the cushion. As shown in TABLE 2 below, an89.3% spore reduction level (level of bioburdens on the instrument) wasachieved after a first stab of the instrument into the cushion of thepresent disclosure. A second stab increased the spore reduction level to95.6%. A 97.4% spore reduction level was achieved after three insertions(or stabs).

TABLE 2 Cushion of the Prior Art Foam of U.S. Foam Present DisclosurePat. No. 8,231,734 Spore Reduction: 89.3% 82.6% 1 Stab Spore Reduction:95.6% 86.3% 2 Stabs Spore Reduction: 97.4% 96.3% 3 Stabs

As is shown, the cushions of the present disclosure demonstratesimproved spore removal compared to prior art cushions in the first twopasses. The cushions of the present disclosure also demonstrate slightlyimproved performance with three stabs. The cushions of the presentdisclosure also removed almost as many spores in two stabs as the priorart cushion did in three stabs.

Other tests were performed to test the efficacy of the cushion of thepresent disclosure. For example, a test was performed to remove cementdeposit from an instrument. The cement removal test mirrored the resultsof the spore removal test in that each pass with a given instrumentprovided better cleaning. All instruments passed the cleaning thresholdsof the cement removal test with three stabs into foam of the presentdisclosure. Cushions having an IFD in the range of 161-173 lbf cleanedfiles in just two stabs. Cushions having an IFD of 156 lbf had one fileclean in two stabs and one file clean in three stabs.

The cushions of the present disclose may provide several advantages overthe prior art cushions. For example, the cleaning properties of acushion in contact with a rotating instrument may be greatly enhancedbecause it takes less time to clean the instrument and contaminants aregreatly removed while the instrument is moving in a rotary fashion inthe cushion. This means the instrument may be cleaned without removingthe rotary bit from the drill. Another advantage may be that rotatinginstruments that are vertically inserted in the cushion may not tear orshear the cushion, which nearly eliminates the chance of introducingcushion debris to an instrument and potentially introducing such debrisback into the tooth. Another advantage may be that that the structuralfeatures of the cushion may help it load into and conform better to thesocket-member. This may help eliminate the dislodgement during the useof loading and cleaning of all instruments, particularly rotaryinstruments, which may be due to the firmness and compressive pressurethe inserted cushion exhibits against the walls of the cup. Anotheradvantage may be that the cushion does not tear during horizontalcleaning as the cushion is much more tear resistant than prior artcushions, such as the prior art cushion. Another advantage may be thatstationary or hand instruments may also be cleaned better using thecushion of the present disclosure.

Another advantage may relate to deformation as the cushion of thepresent disclosure may not deform under normal autoclave processing(heat) and thereby the loading and retention performance of the cushionas it is seated in the socket-member may not be compromised. In anautoclave the cushion of the present disclosure was stiff enough toresist significant deformation when placed under a load. The prior artcushion did not rebound.

In an embodiment of the present disclosure, a porous material, such as afoam cushion, is provided for insertion and/or rotary cleaning ofinstruments, including hand and rotary instruments. Such porous materialmay include an at least partially open-cell foam body and a surface. Theporous material may be configured to substantially grip the instrumentto remove a substantial portion of the contaminants from the instrumentwhile the instrument is rotating and in contact with the porousmaterial, but while not tearing, gripping, or shredding the porousmaterial while rotating in contact with the porous material.

While the present description has been provided with reference to theforegoing embodiments, those skilled in the art will understand thatmany variations may be made therein without departing from the spiritand scope defined in the following claims. The description should beunderstood to include all novel and non-obvious combinations of elementsdescribed herein, and claims may be presented in this or a laterapplication to any novel and non-obvious combination of these elements.The foregoing embodiments are illustrative, and no single feature orelement is essential to all possible combinations that may be claimed inthis or a later application. Where the claims recite “a” or “a first”element or the equivalent thereof, such claims should be understood toinclude incorporation of one or more such elements, neither requiring,nor excluding, two or more such elements.

What is claimed is:
 1. A method of cleaning contaminated instruments,comprising: providing a porous material with an at least partiallyopen-cell foam body having an interior region and a surface, wherein thebody has an IFD within a range of 121 lbf to 198 lbf; contacting thecontaminated instrument such that the porous material substantiallygrips the instrument; rotating the contaminated instrument while beinggripped by the porous material to remove contaminants; and removing theinstrument from the porous material after rotating the instrument,wherein the removed instrument is substantially free of contaminant andof the porous material.
 2. The method of claim 1, further comprisinginserting the contaminated instrument into the interior region, wherebythe porous material substantially grips the rotating instrument.
 3. Themethod of claim 1, further comprising depressing the contaminatedinstrument substantially horizontally onto the surface of the porousmaterial, whereby the porous material substantially grips the rotatinginstrument.
 4. The method of claim 1, wherein the instrument is rotatingbefore contacting the porous material.
 5. The method of claim 1, furthercomprising removing at least about ninety percent of bioburdens on thecontaminated instrument after a single insertion of the contaminatedinstrument into an interior region of the porous material.
 6. The systemof claim 5, further comprising removing over ninety-five percent ofbioburdens on the contaminated instrument after two insertions of thecontaminated instrument into the interior region.
 7. The system of claim6, further comprising removing over ninety-seven percent of bioburdenson the contaminanted instrument after three insertions of thecontaminated instrument into the interior region.
 8. A method ofcleaning an endodontic file comprising: providing an endodontic filehaving a flute portion and a handling portion, installing the handlingportion of the file in a rotary motor driven dental hand piece, rotatingthe file, providing a cushion member comprised of foam, the cushionmember having a file-receiving surface, stabbing the flute portion ofthe file through the file-receiving surface into the cushion member, andremoving the file from the cushion member, wherein at least part of therotating step is performed between the stabbing and removing steps. 9.The method of claim 8, wherein the rotating step is started before thestabbing step.
 10. The method of claim 8, wherein the file is rotated atapproximately 100 to 1000 RPM while the flute portion of the file ispenetrating the file-receiving surface of the foam.
 11. The method ofclaim 8, wherein the file is rotated at approximately 300 to 350 RPMwhile the flute portion of the file is penetrating the file-receivingsurface of the cushion member.
 12. The method of claim 8, wherein thestabbing step is performed at least twice.
 13. The method of claim 8,wherein the stabbing step is performed at least three times.
 14. Themethod of claim 10, wherein the file is rotated in the foam for at leastapproximately 2 seconds.
 15. The method of claim 8, wherein the file isrotated in the foam for at least approximately 3 seconds.